"It's also important to control the moisture in your home. Humidity at 30 to 50 percent helps reduce mites and mold," Goralski said.

The right-size air conditioner helps cut humidity. Dehumidifiers also work, but they generate heat - so save them for your basement.

Air purifiers can also be useful for removing dust and pollen. Consumer Reports tested their effectiveness in a sealed chamber.

Top-rated portable air cleaners include the Honeywell HPA300 for $250.

"If you have a heating or cooling system that is forced-air, you may want to opt for a thicker filter, which we found more effective. But they may require professional installation to accept them," said Dave Trezza with Consumer Reports.

A good choice is the $29 Filtrete Healthy Living Ultra Allergen filter, which is available online.

And don't forget - your vacuum can kick up dust and aggravate allergies.

Consumer Reports finds these vacuums are good for emissions - the Hoover Windtunnel Max for $180 and the Kenmore Elite for $350.

Allergy and asthma suffers might want to stay away from bagless vacuums, which can stir up dust.

One last tip - change out air conditioning filters regularly. It can make a big difference.